I don't know what this prop would fit but it looks like it will go cheap!
http://cgi.ebay.com/ebaymotors/Brass-prop-Moomba-boat-_W0QQcmdZViewItemQQhashZitem3365d85c3bQQitemZ22075 2010299QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear